Sleep disordered breathing (SDB), described by the frequency of apnea and hypopnea events during sleep, is widely recognized as a highly prevalent but under-diagnosed condition that has a significant role in hypertension, cardiovascular and cerebrovascular disease, impaired cognitive function, hypersomnolence, decrements in daytime functioning and premature all-cause and cardiovascular mortality. Population studies over the 20 years have established the high prevalence of SDB and begun to identify the correlates and outcomes of SDB, but critical questions must be addressed to craft clinical and public health policy regarding the prevention and treatment of SDB. Important period effects that will change the SDB burden are occurring in the US, including aging of the large post World War II birth cohort, enhanced survival of older adults who have had different exposures during midlife to SDB risk factors, and an obesity epidemic. Data to address the public health burden of SDB under these new conditions are lacking. The research proposed here is designed to address the gap in understanding the burden of untreated SDB. With a 5-year continuation of the Wisconsin Sleep Cohort Study, a longitudinal study of SDB and other sleep disorders, we will continue to follow a community sample (n= 1522) of men and women, 30-60 years of age at baseline, who will have aged to 55-85 years over the continuation. With data spanning up to 25 years, with individual trajectories of data on SDB and other factors from middle to older age, we will optimally estimate the role of untreated SDB in preclinical and clinically evident cardiovascular and cerebrovascular disease (CVD/stroke), cognitive impairment, and chronic daytime dysfunction. We will also investigate the impact of age-related risk factors on sleep disorders. To achieve these goals, we will conduct follow-up protocols with overnight polysomnography, state of the art body habitus measures including DXA, echocardiography and vascular imaging, neuropsychologic test batteries, and other tests to extend our rich data on SDB status, risk factors, and outcomes.